In many works, wolves are heard howling at dusk or at night. It is a case of Noisy Nature. Also, it is often a case of not doing the research or Artistic License: wolves don't live in all settings, and they usually howl to communicate with each other, not to establish the mood or tell time. Often overlaps with Cock-a-Doodle Dawn, which is when roosters crow at dawn.

What beautiful music it makes!

This trope has two main types:

Type A
In type A examples, wolf howls are heard to herald the coming of the night. The wolves that do the howling are rarely seen.
Type B
In type B examples, the howls are heard late at night, to reinforce a creepy setting or establish a fearful mood. Again, the wolves are rarely seen.

See also Wolves Always Howl At the Moon and Howl of Sorrow.

Examples of Howling to the Night include:

Type A

Video Games

Type B

Anime / Manga

Film

Video Games